Sewing machine shuttle



Apnl 6, 1948. c. A. NEWHALL SEWING MACHINE SHUTTLE Filed Dec. 5, 1946 2 m 0 I. f f1. 4 1

20 Inventor 11551 h I]. W I

Carl A. Newhall Patented Apr. 6, 1948 UNI TED STAT-ES PATENT F FICE SEWING M H E EHUTTLE Carl A. Newhall, Peabody, Mass, assignor to United Shoe Machinery Corporation, "Flemington, N. J a corporation'of New Jersey ApplicationDecember '5, 1945, ,fierial No. 714,197

The present invention relates to sewing machine shuttles, and more particularly to improved constructions and arrangements of parts for a locking thread supply holder within a sewing machine shuttle of the type disclosed in United States Letters Patent No. 1,905,032, granted on April 25, 1933, on an application filed in thename of Fred Ashworth and No. 2,396,755, granted on March 19, 1946, on an application filed in the name of William F. Shimek.

An object of the present invention is .to improve a sewing machine shuttle and thread holder of the type disclosed in the patents above referred to in such a Way that the thread holder may readily be removed from the shuttle under all circumstances. According to a further object, a construction is provided for locking the thread holder within the shuttle of a sewing machine or for unlocking it, which is operable under all conditions without resorting to the use of complicated parts, the arrangement of which renders difiicult their assemblage.

In the shuttle and thread holder of the patents noted the thread holder is formed with a central hollow stud within which is arranged a pair of telescoping plungers. forces the thread against the inner wall of the shuttle to provide a sewing tension on the thread and the other acts on a retaining s1ide carried by the thread holder to lock the slide in retaining position within the shuttle.

Under some circumstances, particularly when the thread within the holder becomes knotted or snarled or some portion of the thread has an enlargement therein, the tension plunger will be- One of the plungers come forced within the stud portion of the thread holder to such an extent that it will block movement of the locking plunger away from the slide. Under these circumstances the thread may become broken at its point of exit from the thread holder and it will be impossible to remove the holder in the usual way.

According to the present invention a shuttle is provided having a hollow casing within which is secured a thread supply holder formed with a hollow stud and a pair of plungers within the stud, of the type disclosed in said Patent No. 2,396,755, in which a sleeve is inserted within the stud for stopping movement of the tension plunger when an enlargement in the thread passes between the tension plunger and the shuttle casing. The tension plunger is stopped by the sleeve before it reaches a position where slide-releasin movement of the locking plunger is blocked.

Fig. 2 is a sectional view taken along the line II-II of the shuttle illustrated in'Fig. '1;

Rig. 3 is a sectional view on an enlarged scale of the locking slide and tension arrangement of the thread case as illustrated in Fig. 2:; and

Fig. 4 isa further sectional view taken along the line IV-TV of (Fig. 1 showingthe operation of the sleeve of the invention in blocking movement of the ten'sionplunger when an enlargement in the thread becomes jammed between the plunger and the thread case.

The shuttle ,of the accompanying drawings is intended to cooperate with other stitch-forming devices in a shoe-sewing machine and consists of a discoidal shuttle casing tythe rearward end of which is closed and the forward end of which is open to receive a thread holder 8 comprising a similarly shaped container fitting within and forming a closure for the open end of the shuttle casing. From the closed end of the thread holder a h-ollow stud W projects inwardly so as to provide a central support for inserting a thread supply cop l2. Sliding within t-he stud ill a hollow tension plunger I4 is arranged to he acted upon by a coil spring [6 tending to force the plunger against the rear wall of the shuttle casing. The tension plunger forms a central conductin passage or guide for -the thread opening at the outer side of the thread holder with the thread leading from the interior of the thread cop between the plunger and the rear wall of the shuttle casing, as in the prior patents above referred to.

To look the thread case removably in position in the shuttle casing, the holder 8 is provided with a radially projecting flange l8 fitting a slot in the circular side wall of the shuttle casing, and a diametrically movable locking slide 29 retained within a guideway 22 in the front wall of the supply holder is readily movable toward and from a groove 24 in the circular wall of the shuttle casing at the opposite side from the flange l8. To lock the slide 20 within the groove 24, a second hollow plunger 26 is slidahly mounted in the hollow stud and is provided with a reduced end entering a hole 28 (see Fig. 4) formed in the slide. A suitable tool is inserted 3 in the hold 28 to force the plunger rearwardly awayfrom the slide thereby allowing it to be moved into a position for unlocking the slide.

In the shuttle of the patents above referred to, the plungers are urged yieldingly apart by a single compression spring, similar to that indicated at 3t in the drawings, surrounding telescoping portions of the plungers. If an enlargement 3! is encountered in the thread as it moves from the cop to the sewing point in the machine the tension plunger is forced inwardly of the stud I B, as indicated in Fig. 4, and may reach such a position that unlocking movement of the locking plunger 26 is blocked. Under these con ditions the thread becomes jammed inside the thread holder and it is impossible to remove the thread holder from the shuttle casing for adjustment of the thread therein. Any attempt to draw the thread further from the thread holder forces the tension plunger further against the locking plunger and eventually causes the thread to break either inside the hollow stud or so close to the thread holder that no grip can be obtained on the short end remaining.

To prevent movement of the tension plunger from blocking the locking plunger 25, according to the present invention, a thin sleeve 32 is inserted within the hollow stud portion it] of the thread holder and the outside diameter of the looking plunger is reduced suificiently to enable the sleeve to surround this plunger. The sleeve 32 is arranged to engage a flange on the tension plunger and prevent it from moving to a position which will block releasing movement of the locking plunger under any circumstances. Thus, when an en'largment on the thread tends to force the tension plunger inwardly of the stud ill, as illustrated in Fig. 4, the flange on the tension plunger engages the inner end of the sleeve 32 and holds the tension plunger against fur-' ther inward movement. The sleeve is of sufficient length to enable the locking plunger to be depressed and disengaged from the retaining slide 2%] from the position of Fig. 3 to that'of Fig. 4, even with the flange on the tension plunger engaging the inner end of the sleeve.

The sleeve 32 is held in place within the stud l by the slide 29. After insertion within the stud the slide is introduced within the guideway 22 and the opening 28 in the slide is insuflicient in size to receive the full diameter of the sleeve. With such arrangement the sleeve is readily assembled with the other parts of the tensioning and locking means and a simple and effective construction is provided avoiding all of the dini- 4 culties encountered in use with the shuttle disclosed in the prior patents.

The nature and scope of the invention having been indicated and the several features having been described, what is claimed is:

1. A shuttle for shoe sewing machines, comprising a hollow casing, a thread supply holder forming a closure for the shuttle casing provided with a hollow stud projecting into the casing through which the thread passes to the outer side of the holder, and means for removably locking the thread holder to the shuttle casing comprising a locking slide in the end of the thread I V holder arranged to move across the end of the thread holder and to engage a groove in the shuttle casing and pair of plungers in the hollow stud, one of which plungers is pressed against the thread engaging the inner surface of the shuttle casing to provide a tension on the thread and the, other of which plungers is pressed against the slide to lock it in position, in combination with a sleeve inside the stud for stopping movement of the tension plunger when an enlargement in the thread passess between said tension plunger and the shuttle casing before the tension plunger reaches a position where slide releasing movement of the locking plunger is blocked by the tension plunger.

2. A shuttle for shoe sewing machines, comprising a hollow casing, a thread supply holder forming a closure for the shuttle casing provided with a hollow stud projecting into the easing through which the thread passes to the outer side of the holder, and means for removably locking the thread holder to the shuttle casing comprising a locking slide in the end of the thread holder arranged to move across the end of the thread holder and to engage a groove in the shuttle casing and a pair of plungers in the hollow stud, one of which plungers is pressed against the thread engaging the inner surface of the shuttle casing to provide a tension on the thread and the other of which plungers is pressed against the slide to lock the slide in position, in combination with asleeve held inside the stud surrounding the locking plunger by said slide for stopping movement of the tension plunger when an enlargement in the thread passes between said tension plunger and the shuttle casing before the tension plunger reaches a position where the slide releasing movement of the locking plunger is blocked by the tension plunger.

CARL A. NEWHALL. 

